How to avoid this Xvfb error: ES2 Prism: Error - GLX extension is not supported

[Eric Gunther]

On Mon, 2016-12-12 at 14:39 -0500, Long Vu wrote:
> On Mon, Dec 12, 2016 at 2:34 PM, Eric Gunther <egunther at warwick.net>
> wrote:
> > On Mon, 2016-12-12 at 13:51 -0500, Long Vu wrote:
> > 
> > I don't know if this will help, but previously adam had said:
> > 
> > > How are you launching Xvfb? I believe it defaults to 8bpp, but
> > > GLX
> > only
> > > works at 16 or 32bpp.
> > 
> > which I think you hadn't tried yet.
> > 
> 
> Well I did with
> 
> xvfb-run -s '-screen 0 1024x768x24 +extension GLX +iglx' <command>
> 
> I though the adding x24 to the screen is what Adam meant.
> 
> If I miss understood, kindy point out to me because I am not familiar
> with X server options.
> 
> Thanks.
> 
> 
> -- 
> Long Vu | Build Controller | Intelerad | +1-514-931-6222 ext. 7743
> 

Again, don't know, but it would seem as though the 24 is the depth.

As you have referred to bpp before, I assume that is what you mean.
https://en.wikipedia.org/wiki/Color_depth

According to the man page for xvfb 
https://www.x.org/archive/current/doc/man/man1/Xvfb.1.xhtml

"
−screen screennum WxHxD

This option creates screen screennum and sets its width, height, and
depth to W, H, and D respectively. By default, only screen 0 exists and
has the dimensions 1280x1024x8.
"


Where the last number is the depth.  Previously Adam mentioned that GLX
only works at 16 or 32.  I just noticed an inconsistency.  It would
seem feasible to try that command if xvfb-run takes the switches xvfb
does. I am thinking;
xvfb-run -s '-screen 0 1024x768x32'

          or 

xvfb-run -s 'screen 0 1024x768x16'  


If you follow what I am saying. 


-eg